Deburring tumbling media



April 2, 1968 R. w. RICKER 3,375,615

DEBURRING TUMBLING MEDIA Filed Jan. 10, 1966 INVENTOR RICHARD W. ER

ATTORNEY United States Patent ()fifice 3,375,6 Patented Apr. 2., 1968 3,375,615 DEBURRING TUMBLING MEDIA Richard W. Ricker, Cleveland, Ohio, assignor to Ferro Corporation, Cleveland, Ohio Filed Jan. 10, 1966, Ser. No. 519,478 4 Claims. (Cl. 51164.5)

ABSTRACT OF THE DISCLOSURE Angular, generally tabular, tumbling deburring media having substantially sharp primary deburring points, openings positioned in close proximity to said points, said media adaptable to fracture at points of weakness adjacent said openings to provide additional, substantially sharp, deburring points upon fracture and disengagement of the fugitive primary point.

It has been known to utilize fiat, tabular, abrasive shapes having angular corners for knocking the burrs off cast, forged or machined metallic articles, particularly those having grooves, threaded portions or the like, by placing the items to be deburred in a tumbling mill, along with a quantity of deburring media, such as flat ceramic abrasive triangles, parallelograms, stars, etc., anything having sharp points or corners which, during tumbling, can find their way into grooves and crevices for purposes of deburring and cleaning same.

However, one of the drawbacks to angular media used heretofore is that during the deburring process, the sharp corners are quickly abraded, worn and reduced to rounded, curved edges no longer capable of reaching into threads, grooves and crevices for efiicient deburring.

Accordingly, it is an object of this invention to provide a simple, yet very effective, improvement in the form of perforated angular deburring media for more efficient utilization and longer useful life of said media.

It is also an object of this invention to provide an improved method for deburring articles of manufacture.

Another object of this invention is to provide a new and improved article of manufacture comprising an improved deburring shape as an article of manufacture.

FIG. 1 is an example of one preferred form of my new deburring media seen in perspective.

FIG. 2 is a plan view of said improved grinding media depicted in FIG. 1.

FIG. 3 is a plan view of one, worn corner of the article depicted in FIG. 2.

FIG. 4 is a variation of one of the preferred shapes illustrated in FIG. 1.

FIG. 5 is a variation of one of the preferred shapes illustrated in FIG. 1.

Referring now to the drawings, FIG. 1 shows a tabular, triangular shaped piece of grinding media, generally depicted by the reference numeral 1, which, but for the holes 2 therethrough, generally represents the previous form of grinding media normally employed.

Referring to FIG. 2, it will be seen that after a period of use, the sharp corners of the triangle are worn to coincide generally with the dotted are 3 having, in this particular illustration, centers, respectively, situated generally in the vicinity of 4, said arcs striking the two legs of the angle a of the triangle approximately equidistant from the apex thereof as represented roughly by X and X in FIG. 2, wherein X and X are approximately equal.

Previously, when media had been worn down to are 3, as will be readily apparent, the loss of the angles a materially reduced the effectiveness of the grinding media.

However, by forming the grinding media with the holes 2 situated between the legs of the angles a, when the media is worn to the vicinity of are 3, or reasonably close thereto, it will be seen that points of weakness occur generally in the vicinity between points 5 for any given opening, and subsequent tumbling activity tends to fracture the piece or wear it through somewhere between points -5, to provide new, sharp, contact points for reaching into crevices and grooves of articles to be deburred, thereby automatically extending the useful life of the particular piece of deburring media. FIG. 3 depicts one corner of triangle 1, following wear of the sharp angle a to are 3, after which fracture has taken place presenting new, sharp angles for continued efiicient deburring, depicted by reference numerals 6 and 7 in FIG. 3.

FIG. 4 represents a parallelogram having two obtuse and two acute angles for certain types of deburring, and it will be noted a segment of its silhouette (any of its four corners) represents an angular geometric outline (triangle) with openings 2 disposed adjacent the legs of each angle.

FIG. 5 represents another variation in the form of a four pointed star having silhouette segments generally in common with the articles shown in FIGS. 2 and 4.

The articles of this invention may be composed entirely of ceramics such as porcelain, the carbides, or alumina, or they may be manufactured following the technology of abrasive grinding Wheel compounding, wherein particles of ceramic abrasive are bonded together in a predetermined shape by either a vitreous or plastic resin binder. Regardless of how compounded however, the articles of my invention will consist of either substantially inorganic ceramic, or, if bonded, at least 70% of ceramic inorganic abrasive.

Too, while I prefer my openings 2 be circular, it is contemplated that they could be square, triangular, or any other shape, so long as part of the opening coincided generally with some point on are 3.

Naturally, if the opening is situated too far back from the legs of the angle 0:, its purpose will not be served, thus the distance between the opening 2 and either leg of angle a must always be less than one half the widest dimension of opening 2 measured at right angles to the line of bifurcation of angle a.

Thus, briefly stated, my invention comprises an article of manufacture for tumbling deburring, comprising a three dimensional, unitary solid, containing at least 70% by weight inorganic ceramic, which solid presents at least one silhouette representing an angular geometric outline having at least one angle less than said angle having an opening therethrough adjacent the legs thereof, at least a part of said opening coinciding generally with some segment of an arc intersecting both legs of said angle, said point of coincidence occurring nearer the apex of said angle than either point of intersection of said arc with said legs of said angle, said are being convex toward said apex and intersecting each leg of said angle, respectively, approximately equidistant from said apex, said opening being a distance from either of said legs less than half the widest dimension of said opening measured at right angles to the line of bifurcation of said angle.

I claim:

1. An article of manufacture for tumbling deburring, comprising a three dimensional, unitary solid, containing at least 70% by weight inorganic ceramic, which solid presents at least one silhouette representing an angular geometric outline having a multiplicity of angles, at least one angle less than 180, said angles each terminating in a substantially sharp primary point, said angles having an opening therethrough adjacent the legs thereof, said opening generally centered between the legs of said angles and adjacent the primary point thereof, edges of said opening occurring closer to the'legs of said angles than to the apex of said primary points, said article having a point of weakness adaptable to fracture said fracturable point occurring respectively, with respect to each opening, where said opening is in closest proximity to each leg of said angles, said article having a minimum of two openings, each opening spaced apart from other openings by a distance at least one and one-half times the maximum dimension ofone said opening, said article adapted to fracture at said fracturable point of weakness to present additional substantially sharp points over and above said primary point.

2. The article of manufacture of claim 1 wherein said article of manufacture is a unitary solid containing at least 70% by weight inorganic ceramic abrasive, which solid presents at least one silhouette representing an angular geometric outline having at least one acute angle.

3. The article of manufacture of claim 2, wherein said article is generally tabular, has two sides substantially parallel, with said openings through said article generally normal to the parallel faces thereof.

4. The article of claim 1 wherein said substantially sharp point formed by the legs of said angles is fugitive, and at least one said opening rendered discontinuous, at its fracturable point.

References Cited UNITED STATES PATENTS 1,388,463 8/1921 Hardinge 241-184 2,431,870 12/1947 Huenerfauth 51-l64.5 2,978,850 4/1961 Gleszer 5l164.5 X

v FOREIGN PATENTS 1,368,359 6/1964 France.

284,580 2/1928 Great Britain.

HAROLD D. WHITEHEAD, Primary Examiner. 

